The present invention relates to an electric rotating machine, such as a motor and generator, and in particular to an electric rotating machine wherein one stator and two rotors are arranged coaxially.
A rotator core and stator core of an electric rotating machine are formed of layers of thin plates such as silicon-steel plate. Generally, thin plates are joined by welding. However, since a convex projection arises in the welding position, the gap between the cores cannot be made small. That is, if the gap is made small, the core facing the convex projection will interfere with the convex projection.
Hence, the opposite side of a magnetic pole-face is welded so that there is no weld part with a surface (magnetic pole-face) facing another core.
However, in the electric rotating machine in which one stator and two rotors are arranged coaxially as disclosed by JP-A-H9-275673 published by the Japanese Patent Office in 1997, both the inner and external surfaces of a core in the middle are magnetic pole-faces, so the opposite side of the magnetic pole-face cannot be welded as mentioned above.
If one of the surfaces is welded, the gap with the core facing the welded surface cannot be made small.
It is therefore an object of this invention to eliminate the above-mentioned convex projection, and make the gap between cores small.
In order to achieve above object, this invention provides an electric rotating machine, comprising a middle core comprising plural plates (2A, 23A) stacked in an axial direction, an outer core disposed outside the middle core, and which rotates relative to the middle core, and an inner core disposed inside the middle core, and which rotates relative to the middle core. The plural plates are joined to a first fixing member by a connecting member.
According to an aspect of the invention, this invention provides a method of manufacturing an electric rotating machine, the machine having a middle core comprising plural plates stacked in an axial direction, an outer core disposed outside the middle core which rotates relative to the middle core, and an inner core disposed inside the middle core which rotates relative to the middle core, the method comprising joining the plural plates to a first fixing member by a connecting member, and finishing the inner and outer circumferential surfaces of the plural plates in the state where the plural plates are joined only to the first fixing member.
The details as well as other features and advantages of this invention are set forth in the remainder of the specification and are shown in the accompanying drawings.